With the development of display technology, LCD (liquid crystal display) devices have become the most common display devices. An LCD has advantages such as high space utilization, low power consumption, no radiation and low electromagnetic interference, and therefore is widely used in communication tools such as televisions, mobile phones, and tablet computers.
At present, one direction of the development of the display technology is high resolution and high PPI (Pixel per Inch). While fine and delicate ultra high definition display is achieved, a corresponding pixel size would be reduced with an increase of resolution and PPI. While the pixel size is reduced, a metal area per unit area would be increased; a corresponding aperture ratio would be reduced; and generally, corresponding transmittance would also be reduced greatly. This has become a bottleneck for a high resolution and high PPI pixel design.
As shown in FIG. 1, a VA (vertical alignment) liquid crystal display device is taken as an example, and a color filter layer is provided on an array substrate, i.e., COA (Color filter On Array) technology is used in a pixel structure. A left side portion in FIG. 1 shows a TFT (Thin Film Transistor) structure, and a right side portion shows a storage capacitor (Cst) structure that is configured to provide a pixel deflection voltage. The storage capacitor is composed of a first metal layer 1 and a second metal layer 2. Capacitance is proportional to an overlapping area of the two metal layers. Since the first metal layer 1 and the second metal layer 2 are optically opaque metals, the aperture ratio is seriously affected. In addition, an optically opaque design is used in an area above a data line for shielding light, and a product with a DBS (Data line BM Less) design is shown in FIG. 2. A transparent common electrode 30 is provided above a data line 20 for shielding light. In consideration of improving transmittance, a distance B between the common electrode 30 and a pixel electrode 40 is usually minimized. Thus, a manufacturing difficulty is increased. An entire optically opaque area above the data line is shown as an area A in FIG. 2 including the common electrode 30, a double 13 area, and overlapping areas of the pixel electrodes 40 with shielding metals 10. As a result, an existing display device has a low aperture ratio, which leads to a technical problem of low transmittance.